Linkage assembly for folding tables and the like

ABSTRACT

The folding table includes a pair of U-shaped leg units, each comprising two legs connected by an apron member. The leg units are pivotally attached to opposite ends of a table top, having side apron members, by a compact linkage assembly located at each corner of the table and concealed by the apron members. Each linkage assembly includes an inclined link member having one end pivotally attached to a leg unit and the other end pivotally attached to a side apron. Each linkage assembly also includes latch members locking the leg unit to the table top in both the erected and the folded positions and an adjustment device is provided to ensure that the leg members tightly abut the table top side aprons in the locked condition.

[ 51 May 16, 1972 [54] LINKAGE ASSEMBLY FOR FOLDING TABLES AND THE LIKEPaul H. Mitchell, Fort Smith, Ark.

Fort Smith Table & Furniture Co., Fort Smith, Ark.

[22] Filed: Sept. 11, 1969 [21] Appl-.No.: 857,054

[72] Inventor:

[73] Assignee:

2,921,825 1/1960 Spiegel ..l08/132 X 3,190,596 6/1963 Kaminky 108/130 X3,120,976 2/1964 Van Sejoc ..108/138 X Primary Examiner-Paul R. GilliamAtt0rney-Cohn and Powell [57] ABSTRACT The folding table includes a pairof U-shaped leg units, each comprising two legs connected by an apronmember. The leg units are pivotally attached to opposite ends of a tabletop,

[52] U.S.Cl... ..108/l31 having side apron members, by a compact linkageassembly [51] Int. Cl. ..A47b 3/00 I t d h fth H d I d b th 58 1 Fieldof Search ..l08/131-133, 129-130, e at e e y e m members. Each linkageassembly includes an inclined link 108/1 15 member having one endpivotally attached to a leg unit and [56] References Cited the other endpivotally attached to a side apron. Each linl age assembly also includeslatch members locking the leg unit to UNlTED STATES PATENTS the tabletop in both the erected and the folded positions and an adjustmentdevice is provided to ensure that the leg mem 2,075,778 3/1937 Johannsen..108/131 bel-s tightly abut the table top Side aprons in the lockedcondi 2,213,681 9/1940 Symmonds.... .....108/130 lion. 2,478,507 8/1949Peterson ..108/132 2,860,940 1 H1958 De Saussure ..108/133 10 Claims, 6Drawing Figures u l l i Ti H 16 14 16 -15 15- :r-18 18-? H 19 19 |IIll-17 17 I l 16 14 16 H H g 1 ill PATENTEnMmsmz 3.662.694

SHEU 2 BF 2 INVENTOR PAUL H. MITCHELL BY CGMMPWQQQ ATTORNEYS LINKAGEASSEMBLY FOR FOLDING TABLES AND THE LIKE BACKGROUND OF THE INVENTIONThis invention relates to folding tables, and more particularly to suchtables utilizing a compact concealed linkage assembly to effectuate thefolding operation. I

The prior art is replete with examples of folding tables in which thefolding mechanism utilizes collapsible struts and braces which are partof the leg support framework and are attached to the legs some distancebelow the table top. These tables, because of the tendency of thesupport framework to obstruct leg room, are not very satisfactory foruse as conference tables and the like. Further, they lack the clean,contemporary lines which are so desirable in modern offices and homes.

Obviously, it is of great importance for tables to be very rigid in use,and the stiffness of the leg connection to the table top is of paramountimportance. In the case of non-folding tables, the solution of thestiffness problem merely involves making the leg to table top connectionsecure. With folding tables, in which the folding mechanism is to becompact and concealed, the problem becomes acute because this mechanismmust be disposed at the very location where stiffness is most important.

SUMMARY OF THE INVENTION This folding table has no visible braces andthe folding mechanism is sufficiently compact so as to be completelyconcealed behind the apron members when the table is erected.

A linkage assembly, connecting each leg to the table top, permits thefolding operation to be made simply and without interference betweenparts and in particular, the swing-away nature of the linkage assemblyis such that not only the end apron members, but also the side apronmembers have square corners, and the side apron members are cleared bythe legs when the legs are moved to a folded position.

A latching device provides complete rigidity at the connection betweenthe legs and the table top, both in the erected and folded positions. Anadjustment feature obviates the need for close tolerance in the movingparts.

In general, the linkage assembly includes a table top member havingsupport means providing first and second abutment means. A leg memberincluding bearing means engages the first abutment means when the tableis in an erected position and the second abutment means when it is in afolded position.

Link means connects each leg member to the support means, the link meansincluding a first pivot means connecting the link means to the legmember and the second pivot means connecting the link means to thesupport means. Locking means, which includes a latch member pivotallyattached to the support means and a cooperating pin member fixedlyattached to the leg member, locks the table leg to the support means inthe erected and the folded positions of the table. The pivot axis of thelatch member is adjustable to compensate for wear between parts andensure satisfactory initial installation.

Each link means includes a link member havingthe first and second pivotmeans disposed in fixed, spaced relation. The link member is inclined sothat the leg member may be pulled away or swung away from the firstabutment means during the folding operation to prevent interferencebetween the leg members and the support means.

The table top member includes a pair of oppositely disposed side apronmembers, each providing a support means. Each leg is part of asubstantially U-shaped leg unit comprising two legs and a bight-formingapron member, and each leg includes an inner face portion providing atleast part of the bearing means. Each side apron includes a pair ofadjacent face portions at each end, one of the face portions providingthe first abutment means and the other face portion providing the secondabutment means. An elongate extension member couples associated latchmembers to ensure concerted leg movement in the locking of theindividual legs of one of the leg units.

Each leg unit includes a pair of opposed bracket members disposed inside-by-side relation with an associated side apron member. The firstpivot means of each link member connects the bracket member to the linkmember and the second pivot means connects the link member to the apronmember. The first pivot member is disposed substantially equidistantfrom one abutment face in the erected position as it is from the otherabutment face in the folded position. Each latch member is pivotallyattached at one end to a side apron and includes a cam face at the otherend engageable with the pin member to lock the leg member in the erectedand folded positions. The center of rotation of the latch member issubstantially perpendicularly equidistant from the leg member in theerected and folded positions. The extension member projects beyond eachlatch member and is journaled into the side apron members to providepivotal rotation of the latch members which are fixedly attached to theextension member. Each apron member includes an oversize journalreceiving one end of the extension member. The extension member includesa transverse rotating handle facilitating the locking and unlocking ofthe latching means.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a plan view of the undersideof the folding table with the legs in the folded position;

FIG. 2 is a side elevational view taken on line 2-2 of FIG. I, the openposition of the legs being shown in phantom outline;

FIG. 3 is an enlarged, fragmentary, perspective view illustrating thelinkage assembly at one corner of the table;

FIG. 4 is a fragmentary elevational view taken on line 4-4 of FIG. 3,illustrating the erected position;

FIG. 5 is a similar view to FIG. 4 with the leg in the partially foldedposition, and

FIG. 6 is a similar view to FIG. 4 illustrating the folded leg position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now by characters ofreference to the drawings, and first to FIGS. 1 and 2, it will beunderstood that the folding table includes a table top unit 10 havingfoldable table leg units 15 disposed at each end. The table top unit 10includes a table top member 11 having an upper side 12, an underside 13and a pair of oppositely disposed apron members 14, the apron members 14constituting support means. The leg units 15 are adapted to be rotatedfrom an erected position, indicated in phantom outline in FIG. 2, to afolded position substantially parallel with the table top member 11 andadjacent the side apron members 14.

Each of the leg units 15 includes opposed leg members 16 interconnectedby a bight-forming, end apron member 17. The leg units 15 are adapted tobe locked in the erected and folded positions by means of a latchingmechanism operated by an extension member 18 extending between the sideapron members 14, each extension member 18 including a transverse handle19 for latching and unlatching the leg units 15. The leg units 15 arepivotally interconnected to the table top unit 10 by means of linkageassemblies, one of which is generally shown by numeral 20 in FIG. 3. Itwill be understood that four such linkage assemblies 20 are provided inthe preferred embodiments.

As indicated in FIG. 3, the side apron member 14, which constitutes asupport means, is fixedly attached as by screws 21 to the underside 13of the table top element 11. The end apron members 17, on the otherhand, are fixedly attached to the legs members 16 as by screws 22, andin consequence move with the leg members 16 from an erected to a foldedposition as a single unit.

Each side apron member 14 includes an elongate channel member 23 havingopposed flanges 24 and 25. At its ends, each apron member 14 includes areversely disposed short channel element 26 welded or otherwise attachedto the channel member 23 in nested relation. The web member 27 of thechannel element 26 'is preferably flush with the narrower flange 24 ofthe channel member 23. This nested channel arrangement provides the sideapron member 14 with a box end against which a side face of the legmember 16 abuts in the erected position. The side apron member 14 alsoprovides an upper flange 24 against which the leg member 16 abuts in theleg-folded'position, as is clearly illustrated in FIGS. 4 through 6. Theend face 30 and the upper face 31 of each side apron member 14constitute first and second abutment means respectively. Generally, intables of the type under discussion, the legs are preferably ri'ghtangularly disposed to the table top. Consequently, the end face 30 isperpendicular to the table top member 11, and the upper face 31 isparallel to the table top member 11.

Each leg unit includes anoutstanding bracket member 32 which is attachedto the end apron member 17 by means of projecting lugs 33 and 34 weldedor otherwise attached to the flanges of end apron member 17. The bracketmember 32 provides a convenient means by which the leg member 16 isattached to the end apron member 17 by screws 22 to form the leg unit15.

. The bracket member 32 is disposed in side-by-side relation to the web27 of the channel element 26 and, therefore, to the side apron memberl4. A link member 35, constituting a link means, connects the leg unit15 to the table top unit 10. This connection is effectuated by pivotpins 36 and 37. Pin 36, which constitutes a first pivot means, connectsthe link member 35 to the bracket member32. Pin 37 which constitutes asecond pivot means, connects the link member 35 to the web 27.

It will be observed that the bracket member 32 is spaced from the web 27and that the link member 35 is disposed within this space between thebracket member 32 and the web 27. A guide stud 38, constituting a stopmeans, is welded to the bracket member 32 and projects from the bracketmember 32 in adjacent relation to the link member 33 in the erectedposition. This stud 38 assists in guiding leg units 15 during thefolding operation in a manner which will be later described.

The linkage assembly includes a locking means locking the leg member inthe erected and folded positions. The locking means includes a latchmember 40, pivotally attached to the side apron member 14, and a pinmember 41 welded or otherwise attached to the bracket member 32. In thepreferred embodiment, the latch member 40 is fixedly attached as bywelding to the extension member 18. This extension member 18 isjournaled into the web 27 through an aperture 39 provided in the web andextending as it does from side to side of the table p'rovidesforconcerted latch release action between a pair of individual latchmembers 40 to lock one of the leg unit 15. The latch member 40 isdisposed in spaced relation from the face of the web 27 and is locatedon the other side of the bracket member 32 to avoid interference withthe link member 35.

Because of its attachment to the extension memberlB, the latch member 40is pivotally attached at one of its ends to the apron member 14. Thelatch member 40 includes a cam face 42 at its other end which isengageable with the pin member 41 to lock the leg unit 15 in the erectedleg position. The cam face 42 is preferably arcuate in order to exert awedge action on the pin member 41, and hence draw the leg unit 15 intoits ultimate position.

In the preferred embodiment of the linkage assembly 20, the dispositionof parts is such that the latch member 40 locks the leg unit 15 in thefolded position in addition to the erected position. See FIGS. 4 and 6.This convenient arrangement, which requires only one latch member foreach linkage assembly, is efiectuated by disposing the center ofrotation of the latch member 40 substantially equidistantperpendicularly from the end abutment face 30 and the associated rightangularly disposed abutment face 31.

The locking means includes an adjustment device which is capable ofrelocating the latch pivot center slightly. This adjustment deviceobviates the necessity for manufacturing the linking assembly parts toextremely close tolerances. In the preferred embodiment, the adjustmentmeans is effectuated by providing an oversized hole 39 as the journalmeans rotatively receiving the extension member 18. It will be observedthat the extension member 18 includes at each end, a projecting portion43. This projecting portion 43 is engaged by a hook bolt 44 which iscarried by an angle member 45 welded I or otherwise attached to theinside face of the channel web 27.

The hook bolt 44 is relocated by means of nuts 46 and 47, and v ofdisclosure, the operation of the assembly will be briefly summarized.

In the drawings, for purposes of explanation, the table is illustratedin .the upside down position lying on a support surface, such as theground. it will-be assumed that initially, the legs 16 are in their openposition as shown in FIGS. 3 and 4. Each leg unit 15 in unlatched bymoving the handle 19 into an operative, transverse position and rotatingthe handle 19 toward the table top member 11.-The extension member 18and the latch members 40 which are fixedly attached to each end thereof,are likewise rotated, causing the cam face 42 of each latch member 40 torotate out of engagement with the pin member 41. I

Referring now to FIGS. 4, 5 and 6, it will be observed that when thelatch member 40 is unlatched, the couple provided by leg member bearingface 28 abutting the side apron end face 30, and the latch member 40which together hold the leg unit 15 rigidly in place against the tableunit 10, is terminated. Because the axis of the link member 35 betweenpins 36 and 37 is inclined relative to the table top element 11, the legunit 15 may be moved outwardly as well as upwardly so that the bearingface 28 of the leg member 16 clears the abutment face 30. Because ofthis clearance capability, the leg unit 15 may be swung in a clockwisedirection about the center of rotation of the pivot pin 37 withoutsuffering interference from the apron corner 50 which would otherwiseresult; This arrangement obviates any necessity to round the corner 50,and provides a more effective abutment in the erected and foldedpositions. The rotation of the leg unit 15 between the erected andfolded positions is clearly shown in FIG. 5.

1n the preferred embodiment, thepivot pin 36 is disposed the sameperpendicular distance from the abutment face 30 in the erectedposition, as it is from the abutment face 31 in the folded position.Because of this relationship and because the pivot pin 36 maintains aconstant perpendicular distance from the bearing face 28 while the pin37 is spaced a variable perpendicular distance from the face 28, the legunit 15 can rotate relative to both pins 36 and 37. In the embodimentillustrated, the leg member 16 moves through between the erected andfolded positions. The link member 35, however, moves through an anglesubstantially greater than this and in fact, in the amount of With thedisposition of parts as described in the linkage assembly 20, it ispossible to provide that leg unit flange 51, which is adjacent the tableface 13 in line with the abutment face 30 in the folded position. Thisarrangement has con- The stud guide 38, which projects from the bracketmember 32 and is adjacent the link member 35 in the erected position,serves the purpose of guiding therotation of the leg unit 15 from theopen to the folded position. Without this guide 38, it would be possible(see FIG. 4) for the leg member 16 to rotate about the pivot pin 36 in aclockwise direction, thus causing the leg member 16 to engage the corner50. Because of the stud guide 38, the leg member 16 is obliged to pivotabout the pin 37 in a clockwise direction, although it may be movedanticlockwise relative tothe pin 36, thereby clearing the right angularcorner 50. Further, when the leg unit 15 is returned from the foldedposition, the stud guide 38 prevents inadvertent clockwise rotation ofthe leg unit 15 about the pin 36 which would cause the bearing face 28to come into contact with the corner 50.

By providing a journal bearing for the extension member 18, which isessentially an oversize aperture, slight variations in the center ofrotation of the member 18 and hence of the latch member 40 may beeffectuated, which will compensate for wear between the latching partsand particularly between the cam surface 42 and the pin 41. In essence,the hook member 44 combines with parts of the journal aperture toprovide a complete journal. This journal is adjustable simply byadjusting the nuts 46 and 47 at the threaded end of the hook bolt 44.

The latching action provides a lock position of the legs in both theerected position and the folded position by virtue of the latchengagement with the pin 41 which draws the bearing face 28 against thebearing faces 30 and 31 respectively. Because the pin 41 is spaced fromthe corner 50, the abutment portion between the pin 41 and the corner50, and the pin 41 itself in essence, provide a couple resistingclockwise moment applied to the leg member 16. Any tendency for the legunit 15 to rotate in a counterclockwise direction in the erectedposition is resisted by the pin 41, and the abutment portion of thetable face 13 adjacent the end 51 of the leg unit 15.

In the folded position, any tendency for the leg unit 15 to rotate in acounterclockwise direction is resisted by the latch pin 41 and theabutment portion between the pin 41 and the corner 50. Obviously thereis no tendency for the leg unit 15 to rotate in a clockwise direction asit is fully supported in the preferred embodiment in this position.

A particular advantage results from the provision of an inclined linkmember 35. When the table is in its erected, operational position, theload from the table top unit tends to bear on the four leg members 16.If all of the table load is not carried directly by the ends 51 oftheleg units 15, either by design or otherwise, then a portion will becarried by the pins 37 and will be transferred to the bracket member 32by the link members 35 through the pins 36. Because the link member 35is inclined, the vertical load will have a horizontal component tendingto urge the bearing portion 38 of each leg member 16 against associatedabutments 30. This force augments the couple resistance to the rotationof the leg units described above, and provides a secondary resistancecouple.

I claim as my invention:

1. A linkage assembly for folding table legs and the like, comprising:

a. a table top member including a support means providing a firstabutment means and a second abutment means,

b. a leg member including an inner end, and bearing means engaging thefirst abutment means in an erected position and the second abutmentmeans in the folded position,

. link means connecting the leg member to the support means, the linkmeans including a first pivot means connecting the link means to the legmember and a second pivot means connecting the link means to the supportmeans to permit the inner end of the leg member to move translationally,transversely of the table top member, and

d. locking means including separable latch means selectively engageablefor locking the leg member in the erected position.

2. A linkage assembly as defined in claim 1, in which:

e. the support means includes an apron member having at least one sidesubstantially parallel to the table top to provide an abutment face, andan end substantially perpendicular to the table top to provide anotherabutment face, and

f. the leg member includes a side face providing the bearing means, saidside face engaging the apron end in the erected position and the apronside in the folded position.

3. A linkage assembly as defined in claim 1, in which:

e. the table top member includes an upper face,

f. the leg member is substantially upright in the erected position, and

g. in the erected position, the first pivot means is perpendicularlycloser to the upper face and to the leg member than is the second pivotmeans.

A linkage assembly as defined in claim 1, in which:

. the locking means includes a pivotal latch member and a cooperatingpin member and cam means urging the latch member into engagement withthe pin member, and

f. one of the last said members is attached to the support means and theother of said members is attached to the leg member.

5. A linkage assembly as defined in claim 4, in which:

g. the locking means includes adjustment means selectively relocatingthe center of rotation of the latch member.

6. A linkage assembly as defined in claim 1, in which:

. the link means includes a link member,

the link member is disposed in side-by-side relation to the leg member,and

g. one of the last said members includes a stop engaging the other ofsaid members to preclude relative rotation of one of said members in onedirection as the leg moves into the folded position.

A folding table comprising:

a. a table unit including a pair of oppositely disposed side apronmembers attached to the table top unit, each apron member includingfirst and second abutment means,

b. a pair of oppositely disposed, substantially U-shaped leg units eachattached to the table top unit in inwardly folding relation to the otherleg unit, each leg unit including a pair of leg members interconnectedby a bight-forming, end apron member,

0. each leg unit including bearing means engaging the first abutmentmeans in an open leg position and engaging the second abutment means ina folded leg position,

d. like means interconnecting opposite ends of the leg unit toassociated side apron members, each link means including a first pivotmeans connecting said link means to a leg unit and a second pivot meansconnecting said link means to a side apron member to permit the endapron member to move translationally, transversely of the table topunit, and

. locking means including separable latch means selectively engageablefor locking opposite ends of the leg units to the table top unit in theerected position.

8. A linkage assembly as defined in claim 7, in which:

f. each locking means includes a pivotal latch member and a cooperatingpin member,

g. one of the last said members is attached to the apron member, and theother of said members is attached to the leg unit, and

h. an elongate extension member interconnects associated latch membersto lock one of the leg units by rotation of said latch members.

9. A folding table as defined in claim 8, in which:

i. the associated latch members are fixedly attached to the extensionmember to provide concerted latching action,

j. each extension member includes a projecting portion at each endextending beyond each associated latch member to provide the pivotalattachment of the latch members to the apron members,

k. each apron member includes an oversized journal receiving one end ofthe projecting portion in adjustable rela tion, and

latch members whereby rotation of the extension member rotates each ofthe latch members. and

h. the pivot center of each latch member is disposed substantiallyequidistant from its associated pin member in the erected and the foldedpositions whereby the cam face engages said associated pin member inboth the erected and the folded positions.

1. A linkage assembly for folding table legs and the like, comprising:a. a table top member including a support means providing a firstabutment means and a second abutment means, b. a leg member including aninner end, and bearing means engaging the first abutment means in anerected position and the second abutment means in the folded position,c. link means connecting the leg member to the support means, the linkmeans including a first pivot means connecting the link means to the legmember and a second pivot means connecting the link means to the supportmeans to permit the inner end of the leg member to move translationally,transversely of the table top member, and d. locking means includingseparable latch means selectively engageable for locking the leg memberin the erected position.
 2. A linkage assembly as defined in claim 1, inwhich: e. the support means includes an apron member having at least oneside substantially parallel to the table top to provide an abutmentface, and an end substantially perpendicular to the table top to provideanother abutment face, and f. the leg member includes a side faceproviding the bearing means, said side face engaging the apron end inthe erected position and the apron side in the folded position.
 3. Alinkage assembly as defined in claim 1, in which: e. the table topmember includes an upper face, f. the leg member is substantiallyupright in the erected position, and g. in the erected position, thefirst pivot means is perpendicularly closer to the upper face and to theleg member than is the second pivot means.
 4. A linkage assembly asdefined in claim 1, in which: e. the locking means includes a pivotallatch member and a cooperating pin member and cam means urging the latchmember into engagement with the pin member, and f. one of the last saidmembers is attached to the support means and the other of said membersis attached to the leg member.
 5. A linkage assembly as defined in claim4, in which: g. the locking means includes adjustment means selectivelyrelocating the center of rotation of the latch member.
 6. A linkageassembly as defined in claim 1, in which: e. the link means includes alink member, f. the link member is disposed in side-by-side relation tothe leg member, and g. one of the last said members includes a stopengaging the other of said members to preclude relative rotation of oneof said members in one direction as the leg moves into the foldedposition.
 7. A folding table comprising: a. a table unit including apair of oppositely disposed side apron members attached to the table topunit, each apron member including first and second abutment means, b. apair of oppositely disposed, substantially U-shaped leg units eachattached to the table top unit in inwardly folding relation to the otherleg unit, each leg unit including a pair of leg members interconnectedby a bight-forming, end apron member, c. each leg unit including bearingmeans engaging The first abutment means in an open leg position andengaging the second abutment means in a folded leg position, d. likemeans interconnecting opposite ends of the leg unit to associated sideapron members, each link means including a first pivot means connectingsaid link means to a leg unit and a second pivot means connecting saidlink means to a side apron member to permit the end apron member to movetranslationally, transversely of the table top unit, and e. lockingmeans including separable latch means selectively engageable for lockingopposite ends of the leg units to the table top unit in the erectedposition.
 8. A linkage assembly as defined in claim 7, in which: f. eachlocking means includes a pivotal latch member and a cooperating pinmember, g. one of the last said members is attached to the apron member,and the other of said members is attached to the leg unit, and h. anelongate extension member interconnects associated latch members to lockone of the leg units by rotation of said latch members.
 9. A foldingtable as defined in claim 8, in which: i. the associated latch membersare fixedly attached to the extension member to provide concertedlatching action, j. each extension member includes a projecting portionat each end extending beyond each associated latch member to provide thepivotal attachment of the latch members to the apron members, k. eachapron member includes an oversized journal receiving one end of theprojecting portion in adjustable relation, and l. adjustment means isattached to each projecting portion to selectively locate the latchingmember within the journal.
 10. A folding table as defined by claim 9, inwhich: f. each locking means includes a pivotal latch member attached tothe apron member at one end and including a cam face at the other end,and a cooperating pin member attached to the leg and engageable by thecam face, g. an elongate extension member interconnects associated latchmembers whereby rotation of the extension member rotates each of thelatch members, and h. the pivot center of each latch member is disposedsubstantially equidistant from its associated pin member in the erectedand the folded positions whereby the cam face engages said associatedpin member in both the erected and the folded positions.